New Study Finds Hemp Insulation is Carbon Negative

A new study funded by the American Chemical Society, and published in the journal Environmental Science and Technology, has found that insulation made from hemp is carbon negative, meaning that its production has no negative effect on the environment, and may be beneficial. The study examined the environmental impact involved with the entire production process of making hemp insulation, from harvesting, to the placement of the final product.

As part of the study, researchers compared hemp insulation to rock wool – one of the most common used insulation types – and found the insulation made from hemp to be lighter, and significantly more sustainable. Researchers conclude that; “Indeed, the direct comparison between hemp-based and rock wool insulator mat shows the much higher sustainability of hemp.”

Here’s the study’s abstract in its entirety:

The aim of this research is to assess the sustainability of a natural fiber, such as hemp (Cannabis sativa), and its use as thermal insulator for building applications. The sustainability of hemp was quantified by life cycle assessment (LCA) and particular attention was given to the amount of CO2eq of the whole process, and the indicator greenhouse gas protocol (GGP) was selected to quantify CO2eq emissions. In this study also CO2 uptake of hemp was considered. Two different allocation procedures (i.e., mass and economic) were adopted. Other indicators, such as Cumulative Energy Demand (CED) and EcoIndicator99 H were calculated. The production of 1 ha yielded 15 ton of hemp, whose global warming potential (GWP100) was equal to about −26.01 ton CO2eq: the amount allocated to the technical fiber (20% of the total amount of hemp biomass) was −5.52 ton CO2eq when mass allocation was used, and −5.54 ton CO2eq when economic allocation was applied. The sustainability for building applications was quantified by considering an insulation panel made by hemp fiber (85%) and polyester fiber (15%) in 1 m2 of wall having a thermal transmittance (U) equal to 0.2 W/m2_K. The environmental performances of the hemp-based panel were compared to those of a rockwool-based one.